DA0-002 Data Acquisition and Preparation Practice Test 9 — 15 Questions

Question 1

Which THREE are best practices for acquiring data via web scraping? (Select exactly 3)

Accepted Answer

Respect robots.txt. Option B is correct because robots.txt is the standard mechanism (the Robots Exclusion Protocol) by which site owners declare which paths crawlers may access, and honoring it keeps scraping ethical and within the site's stated permissions. Option C is correct because setting a descriptive User-Agent header identifies your crawler and provides contact information, letting administrators recognize and reach you rather than blocking you as an anonymous bot. Option E is correct because limiting request rate (e.g., throttling to a modest number of requests per second and honoring Retry-After on 429/503 responses) avoids overloading servers and reduces the chance of being rate-limited or banned. Option A does not belong because rotating multiple IP addresses to evade blocks is an evasion technique, not a best practice, and can violate terms of service. Option D does not belong because ignoring terms of service and scraping indiscriminately is unethical and often unlawful, contrary to responsible scraping.

Answer

Use multiple IP addresses

Answer

Scrape all data without regard to terms

Question 2

A marketing analyst needs to combine customer data from a CRM database with social media engagement data from a third-party API. Which data acquisition method is most appropriate?

Accepted Answer

API integration. API integration is the most appropriate method because it allows the analyst to programmatically retrieve structured social media engagement data directly from the third-party service's RESTful or GraphQL API endpoints. This approach ensures real-time or near-real-time data synchronization, supports authentication (e.g., OAuth 2.0), and returns data in standardized formats like JSON or XML, which can be directly ingested into the CRM system without manual intervention.

Answer

Web scraping

Answer

Manual data entry

Answer

Batch file upload

Question 3

A data analyst is tasked with collecting data from multiple spreadsheets provided by different departments. Each spreadsheet has different column names and formats. What is the best first step?

Accepted Answer

Develop a data dictionary and standardize column names. Developing a data dictionary and standardizing column names ensures consistency across all data sources before loading, reducing errors and facilitating integration. Immediately loading data can cause inconsistencies. Discarding mismatched data loses potentially valuable information. Using a machine learning model is an unnecessary and complex first step.

Answer

Discard any mismatched data

Answer

Use a machine learning model to clean data

Answer

Immediately load all data into a database

Question 4

A data engineer is designing an ETL pipeline to extract sales data from a legacy on-premise database and load it into a cloud data warehouse. The database is slow and queries during business hours affect performance. Which extraction strategy minimizes impact?

Accepted Answer

Incremental extraction using Change Data Capture (CDC). Incremental extraction using Change Data Capture (CDC) minimizes impact on the legacy on-premise database by reading only the changed rows (inserts, updates, deletes) from transaction logs or change tables, rather than issuing heavy SELECT queries. This avoids full table scans or frequent queries during business hours, preserving database performance for operational workloads.

Answer

Query the database with SELECT * every hour

Answer

Full table extraction nightly

Answer

Use a database log shipping

Question 5

A research firm is acquiring data from public government databases via API. The API rate limits at 100 requests per minute. They need to download 10,000 records, but each request returns a maximum of 100 records. What is the most efficient approach to ensure complete acquisition without being blocked?

Accepted Answer

Use a retry logic with exponential backoff and pagination. Pagination with retry logic using exponential backoff allows the firm to send requests in a controlled manner, respecting the rate limit and handling potential failures. Sending all requests in parallel would likely exceed the rate limit and cause blocking. Downloading one record per second is too slow. Requesting a data dump via email is inefficient and may not be supported.

Answer

Request a data dump from the government via email

Answer

Download one record per second

Answer

Send all requests simultaneously in parallel

Question 6

Which TWO are valid data acquisition methods? (Select two.)

Accepted Answer

Web scraping. Web scraping (A) is a valid data acquisition method because it programmatically extracts data from web pages, typically via HTTP requests and HTML parsing (e.g., using libraries like BeautifulSoup or Scrapy), making it a recognized way to collect data from sources that lack a formal data feed. API calls (C) are also a valid acquisition method, since they retrieve structured data directly from a service's application programming interface using protocols such as REST/HTTP or SOAP, often returning JSON or XML payloads. In contrast, data normalization (B) is a data preparation/transformation step that scales or restructures values, not a way to obtain data. Data encryption (D) is a security control that protects data confidentiality, and data profiling (E) is an analysis technique that examines data quality and structure — neither acquires new data.

Answer

Data normalization

Answer

Data encryption

Answer

Data profiling

Question 7

Which THREE are challenges in acquiring data from external sources? (Select three.)

Accepted Answer

Licensing restrictions. Licensing restrictions (C) are a genuine external-data acquisition challenge because third-party providers impose contractual terms, usage caps, and redistribution limits that can legally block or constrain how the data is ingested and reused. Rate limiting (D) is correct because external APIs and feeds typically enforce request quotas (e.g., HTTP 429 responses, tokens per minute), forcing throttling, retries, or batching that complicate acquisition. Data format inconsistency (E) is correct because external sources deliver data in heterogeneous schemas and encodings (JSON, XML, CSV, proprietary formats, differing date/number conventions), requiring parsing and normalization before use. Data redundancy (A) is an internal data-quality issue about duplicate records rather than an external acquisition obstacle, and unauthorized access (B) is a security concern affecting data protection, not a challenge inherent to acquiring data from outside sources.

Answer

Data redundancy

Answer

Unauthorized access

Question 8

A retail company's data analytics team needs to acquire point-of-sale (POS) transaction data from 200 stores daily. Each store sends a CSV file via email at the end of the day. The files often arrive late, have inconsistent column names (e.g., "StoreID", "Store_ID", "store_id"), and occasionally contain corrupted rows. The team manually processes these files, leading to frequent errors and delays. The company wants to automate the acquisition process to ensure data is available by 9 AM the next business day with high quality. Which approach best addresses these issues?

Accepted Answer

Create a script to automatically download email attachments, validate and standardize columns, and flag corrupted rows for review. It directly addresses all three issues: automating the retrieval of email attachments (handling late arrivals), standardizing inconsistent column names via a script (e.g., mapping 'StoreID', 'Store_ID', 'store_id' to a canonical schema), and implementing validation logic to flag corrupted rows for manual review. This approach ensures data is processed reliably by 9 AM without manual intervention, meeting the automation and quality requirements.

Answer

Hire a data entry contractor to manually check and re-enter data

Answer

Ask stores to use a standardized web form to enter data directly into a cloud database

Answer

Implement a VPN so stores can connect to the central database and write transactions in real time

Question 9

A healthcare organization collects patient questionnaire data via paper forms at clinics. The forms are scanned and sent to a central office, where staff manually enter data into an electronic system. This process is slow and error-prone. The organization wants to reduce manual entry errors and speed up data availability. Which method should they adopt?

Accepted Answer

Use optical character recognition (OCR) to digitize the forms and automatically populate the database. Using optical character recognition (OCR) to digitize the paper forms and automatically populate the database directly addresses the goal of reducing manual entry errors and speeding up data availability. OCR converts scanned images of text into machine-readable data, eliminating the need for manual transcription and enabling faster processing. This method is well-suited for structured forms like patient questionnaires.

Answer

Continue manual entry but double-check all entries

Answer

Send forms to an external data processing company

Answer

Require patients to fill out forms online at home

Question 10

A logistics company receives GPS tracking data from fleet vehicles at 1-second intervals via a cellular network. The data is used to optimize routes and monitor driver behavior. Recently, the data acquisition system has been missing updates for some vehicles when they pass through tunnels or remote areas. The data team notices gaps during these periods. The company needs a solution to ensure near-real-time data continuity. What should they do?

Accepted Answer

Implement a store-and-forward mechanism that buffers data on the vehicle's onboard unit and uploads when connectivity resumes. A store-and-forward mechanism buffers GPS data locally on the vehicle's onboard unit during connectivity loss (e.g., in tunnels) and automatically uploads the backlog when cellular connectivity resumes. This ensures data continuity without requiring real-time transmission, directly addressing the intermittent connectivity issue while maintaining near-real-time updates.

Answer

Use a hybrid approach that combines cellular and Wi-Fi networks

Answer

Increase the frequency of data transmission to every 0.5 seconds

Answer

Switch to a satellite-based GPS system

Question 11

A data analyst is performing data acquisition from multiple source files. Which TWO data profiling tasks should the analyst complete before loading the data into the target system?

Accepted Answer

Verify data types and formats. Option B (Verify data types and formats) is correct because data profiling must confirm that each source column's actual data type (e.g., integer, string, date) and format (e.g., YYYY-MM-DD, decimal separators) match what the target system expects, preventing load failures or silent corruption. Option E (Identify missing values and nulls) is correct because profiling must detect NULLs, empty strings, and placeholder values so the analyst can decide on imputation, defaulting, or rejection rules before loading. Option A (Create a dashboard for stakeholders) is a downstream reporting activity, not a pre-load profiling task. Option C (Build a linear regression model) is predictive analytics performed after data is cleansed and loaded, not profiling. Option D (Perform cluster analysis) is an unsupervised modeling technique also done post-load, so it does not belong in pre-load data profiling.

Answer

Create a dashboard for stakeholders

Answer

Build a linear regression model

Answer

Perform cluster analysis

Question 12

A large retail company is integrating customer data from two separate CRM systems into a new data warehouse. System A stores customer IDs as integers (e.g., 12345), while System B stores them as alphanumeric strings (e.g., 'CUST-12345-X'). Additionally, some customers exist in both systems but with slight name variations (e.g., 'John Smith' vs 'Jon Smith'). The data warehouse requires a unified customer table with a single unique identifier for each customer. The analyst needs to design the data acquisition process. Which of the following is the most appropriate first step?

Accepted Answer

Perform data profiling to analyze data distributions, data types, and quality issues in each source. Data profiling is the foundational first step in any data integration project. It systematically assesses source data types, formats, completeness, and quality issues (e.g., integer vs. alphanumeric IDs, name variations) before designing transformation logic. Without profiling, subsequent steps like fuzzy matching or ID standardization risk being built on incorrect assumptions about the data.

Answer

Use a simple crosswalk table based on exact name matches to link records

Answer

Load all data from both systems into a staging table, then run a fuzzy matching algorithm to identify duplicates

Answer

Standardize all customer IDs to a common format (e.g., UUIDs) and then merge the tables

Question 13

A data analyst needs to retrieve all unique job titles from an employees table. Which SQL keyword should be used in the SELECT clause?

Accepted Answer

DISTINCT. The DISTINCT keyword in a SELECT clause eliminates duplicate rows from the result set, returning only unique combinations of the selected columns. When applied to a single column like job_title, it returns each job title exactly once, which is precisely what the analyst needs. DISTINCT operates on the entire row of selected columns, so SELECT DISTINCT job_title FROM employees yields the unique list of titles.

Answer

UNIQUE

Answer

REMOVE DUPLICATES

Answer

FILTER

Question 14

A data analyst is profiling a new dataset containing customer information. When assessing data quality, which metric would be most appropriate to determine if the 'email' column contains valid email addresses?

Accepted Answer

Pattern analysis. Pattern analysis is the correct metric because it validates data against a defined format or regular expression — exactly what's needed to confirm that values in the 'email' column conform to the structure of a valid email address (e.g., user@domain.tld). Data profiling tools use pattern/format analysis to detect values that deviate from expected structures, making it the appropriate quality dimension for format validation.

Answer

Null count

Answer

Cardinality

Answer

Row count

Question 15

A data analyst is working with a sales table that contains columns: sale_id, product_id, sale_date, and amount. They need to calculate a 7-day moving average of sales amount for each product, ordered by sale_date. Which window function syntax should they use?

Accepted Answer

AVG(amount) OVER (PARTITION BY product_id ORDER BY sale_date ROWS BETWEEN 6 PRECEDING AND CURRENT ROW). The correct syntax uses AVG with OVER, partitioning by product_id to calculate per product, ordering by sale_date, and specifying ROWS BETWEEN 6 PRECEDING AND CURRENT ROW to include the current row and the previous six rows, yielding a 7-day moving average.

Answer

AVG(amount) OVER (PARTITION BY product_id ORDER BY sale_date)

Answer

AVG(amount) OVER (ORDER BY sale_date ROWS BETWEEN 6 PRECEDING AND CURRENT ROW)

Answer

SUM(amount) OVER (PARTITION BY product_id ORDER BY sale_date ROWS BETWEEN 6 PRECEDING AND CURRENT ROW)